( 199 ) 



Wtaj the closed branch has got detached from the vapour branch, 

 and has fnrtlier contracted. At the temperatui-e t^^ the distance between 

 the sohibUity isotherm ƒ j/'j and the liquid curve has increased, and 

 the closed branch has vanished, after having contracted to a point. 



4. In the figs. 6, 7 and 8 I have drawn the t'-.v-sections of the 

 ?>.t?-^space diagram for the case discussed here; they follow immediately 

 from the z'-i'-sections, given by me last year ^). 



The section indicated by continuons lines in Fig. 6 holds for the 

 triplepoint temperature t^^. There aecb is the region for liquid -}- va- 

 pour, e h c the three phase triangle, li e d the region for solid 

 jB -}- vapour, bcfm the liquid region and chnf the region for solid 

 B + liquid. 



The curve for solid-fluid or the solubility isotherm r/^c/ meets 

 the metastable vapour branch e d exactly on the line for the substance 

 B, because at the triplepoint temperature of B the vapour which is 

 in equilibrium with solid B, is perfectly the same as that which is 

 in equilibrium with liquid B. 



At a somewhat higher temperature the curve for soli<l-tluid cuts 

 the vapour and liquid curve twice each, just as was the case in 

 the j9-.r-diagram. The curve for solid-fluid has then a shape as is 

 indicated by the dotted line /\ c^ e^ (^\ c\/\ in fig. 6"). Just as in 

 the p-ti'-diagram, this line cuts a piece out of the liquid-vapour region ; 

 in consequence we get two separated regions for liquid and Aapour 

 viz. «1 (?i Cj b^ and e\ d^ h^ g\. From this particular situation ensues 

 further the existence of two three phase triangles, viz. Ci t\ (j^ and 

 c'l^'i^i, between which is situated the region for solid i> -}- gas 

 g^e^e'i, two liquid regions biC^/\m and hiC\/\' and two regions 

 for solid i? -}- liquid viz. <j^c^f\ and (Jic\f\'. 



With increase of temperature the line solid i> -|- fluid assumes the 

 shape of a loop, as is indicated by the Vine fee' e c' f ' in fig. 7 ; on 

 this follows immediately detaching of a part, splitting up into two bran- 

 ches, viz. into the Vme f\ c\c^fi and the closed line i\e\o. At the 

 maximum three phase temperature (fig. 8) the line ƒ c ƒ ' touches the 

 liquid line and the closed line e o e touches the vapour line. Above 

 this temperature the two lines get detached from the liquid, respec- 

 tively the vapour line and the closed line (.\ o^ e^ disappears as a point 

 in the metastable region. 



1) These Proc. Vol. VI, p. 484. 



^) At a temperature, only very little higher than the triplepoint temperature, 

 a part of the branch e'l c'j f'l will fall outside the line for B. 



